As for the Mahdi, Sunni Muslims disagree with the Shiite belief regarding him. “The Sunni Muslims believe in [the coming of] Imam Mahdi but they don’t believe, like the Shiites, that he went into concealment/occultation. They believe that he will yet to be born from the progeny of the Ahl al-Bayt, or the Family of the Prophet (peace and blessings be upon him). The Sunnis also believe that he will fill earth with justice after it has been filled with oppression and corruption. His coming is one of the great signs of the Hour.”

“The main difference nowadays between the Ahl-as-sonna (Sunnis) and the Twelvers Shiites is the question of Imamate, or the religious leadership and authentic authority after the death of prophet Muhammad (peace be on him). For the Sunni group, there is no specific religious source (Qur’an or Hadith) regarding the leadership of the Caliphs who came after prophet Muhammad (peace and blessings be upon him), i.e., Abou Bakr, Omar, Othman, and Ali, etc…., while for the Shiite group, there is Hadith mentioning the legitimate inheritance of leadership to Ali. And this is where the difference started. Another difference is that the Sunnis believe that after the prophets, there is no person who is exempt from major sinful acts and selected by God, while for the Shiite, there is the belief that the first twelve Imams after prophet Muhammad who are descendants from his family, are exempt from these sins, they behave like prophets but do not receive any revelations. There are of course other major differences, but due to the shortage of time, we will stop here. The best thing to learn about this topic is to consult a book or an encyclopedia that details the Creed of the Twelver Shiites.” 

Having stated the above, let’s make it clear that Islam calls for unity and solidarity. Both Sunnis and Shiites are required to work together and try to overcome their points of difference or forget about them, simply because the Ummah is facing a plight and both parties are targeted by one enemy.

Here, we’d like to stress the fact that at a time when the enemy of Islam encroaches the Muslim Ummah, elements of enhancing unity should dominate and disputes between different Muslim groups and sects are to be avoided.

Hence, Muslims should beware of all routes and channels that may lead to divisions, differences and conflicts among them. They should abide by the Qur’an and Sunnah, which are the assured means of salvation. Almighty Allah says: (And hold fast, all of you together, by the covenant of Allah and be not divided among yourselves; and remember with gratitude Allah’s favor on you; for ye were enemies and He joined your hearts in love, so that by His Grace, ye became brethren; and ye were on the brink of the pit of Fire, and He saved you from it. Thus doth Allah make His Signs clear to you: That ye may be guided. ) (Aal `Imraan 3: 103)
In our day and age, it is more important to stress points of agreement rather than points of disagreement and to try to bring a bridge between the Sunnah and the Shi`ah without compromising any Islamic values, because what unites Muslims is much greater than what disunites them.